, Volume 155, Issue 2, pp 397–403

Can variation in risk of nest predation explain altitudinal migration in tropical birds?

Behavioral Ecology - Original Paper

DOI: 10.1007/s00442-007-0897-6

Cite this article as:
Boyle, W.A. Oecologia (2008) 155: 397. doi:10.1007/s00442-007-0897-6


Migration is among the best studied of animal behaviors, yet few empirical studies have tested hypotheses explaining the ultimate causes of these cyclical annual movements. Fretwell’s (1980) hypothesis predicts that if nest predation explains why many tropical birds migrate uphill to breed, then predation risk must be negatively associated with elevation. Data from 385 artificial nests spanning 2,740 m of elevation on the Atlantic slope of Costa Rica show an overall decline in predation with increasing elevation. However, nest predation risk was highest at intermediate elevations (500–650 m), not at lowest elevations. The proportion of nests depredated by different types of predators differed among elevations. These results imply that over half of the altitudinal migrant bird species in this region migrate to safer breeding areas than their non-breeding areas, suggesting that variation in nest predation risk could be an important benefit of uphill migrations of many species.


Costa Rica Elevational gradients Evolution of migration Tropical rainforest 

Supplementary material

442_2007_897_MOESM1_ESM.tif (22.4 mb)
Location and elevation of eight study sites on the Atlantic slope of Costa Rica: La Selva Biological Station (LS1 and LS2), 40 m and 120 m; near the Quebrada Gonzalez ranger station (QB) in Braulio Carrillo National Park (BCNP), 500 m; Selva Tica reserve (ST), 650 m; Rara Avis reserve (RA), 820 m; near the Puesto Zurquí ranger station in BCNP (PZ), 1650 m; near the Chateau Barva refuge in BCNP (CB), 2050 m; near the peak of Barva volcano in BCNP (BV), 2780 m (TIF 22895 kb)

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  1. 1.Department of Ecology and Evolutionary BiologyUniversity of ArizonaTucsonUSA
  2. 2.Department of BiologyThe University of Western OntarioLondonCanada

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